WO2020162110A1 - Fuel injection system - Google Patents

Abstract

This fuel injection system includes: at least two injectors (40, 50) that inject gas fuel into an engine (20); a fuel tank that stores the gas fuel; and a delivery pipe that supplies the gas fuel to each of the plurality of injectors from the fuel tank. The fuel injection system comprises: a wear amount estimation unit (72); and a determination unit (73). The wear amount estimation unit estimates the wear amount of each of the plurality of injectors. The determination unit determines which injector from among the plurality of injectors is to be preferentially operated on the basis of the wear amount of each injector estimated by the wear amount estimation unit.

Description

Fuel injection system Cross-reference of related applications

This application is based on Japanese Patent Application No. 2019-020536 filed on February 7, 2019, and claims the benefit of its priority, and the entire contents of the patent application are Incorporated herein by reference.

The present disclosure relates to a fuel injection system.

Conventionally, there is a vehicle fuel injection system described in Patent Document 1 below. In the fuel injection system described in Patent Document 1, compressed natural gas (hereinafter, abbreviated as “CNG”) is used as fuel for the internal combustion engine, and the CNG fuel is injected into the internal combustion engine by the injector. In the fuel injection system described in Patent Document 1, when the fuel temperature difference between the cylinders of the internal combustion engine is within a predetermined allowable range during stratified combustion, the fuel injection amount and injection are performed based on the average temperature and pressure of the fuel. The fuel injection control of the internal combustion engine is performed by correcting the timing. In addition, when the fuel temperature difference between the cylinders is out of a predetermined allowable range during stratified combustion, this fuel injection system switches to homogeneous combustion and corrects the injection amount based on the average temperature and pressure of the fuel. Performs fuel injection control of the internal combustion engine.

JP, 2005-240581, A

When liquid fuel is used as the fuel for the internal combustion engine, the liquid fuel can be used for boundary lubrication of the injector. However, when a gas fuel such as a CNG fuel is used as the fuel of the internal combustion engine like the fuel injection system described in Patent Document 1, it becomes difficult to boundary lubricate the injector with the fuel. Therefore, in a fuel injection system that uses gas fuel, wear tends to be promoted in the sliding portion of the injector, leaving room for improvement in durability of the injector.

An object of the present disclosure is to provide a fuel injection system capable of improving the durability of an injector that injects gas fuel.

A fuel injection system according to an aspect of the present disclosure supplies at least two injectors that inject gas fuel to an engine, a fuel tank that stores gas fuel, and supplies gas fuel to each of the injectors from the fuel tank. It has a delivery pipe. The fuel injection system includes a wear amount estimation unit and a determination unit. The wear amount estimation unit estimates the wear amount of each of the plurality of injectors. The determination unit determines which of the plurality of injectors is to be preferentially operated based on the wear amount of each injector estimated by the wear amount estimation unit.

According to this configuration, a more appropriate injector can be preferentially operated according to the wear amount of the plurality of injectors, so that the durability of the injector that injects the gas fuel can be improved.

FIG. 1 is a diagram schematically showing a schematic configuration of the fuel injection system of the first embodiment. FIG. 2 is a block diagram showing an electrical configuration of the fuel injection system of the first embodiment. FIG. 3 is a flowchart showing a procedure of processing executed by the control device of the first embodiment. FIG. 4 is a flowchart showing a procedure of processing executed by the control device of the second embodiment. FIG. 5 is a flowchart showing a procedure of processing executed by the control device of the third embodiment. FIG. 6 is a flowchart showing a procedure of processing executed by the control device of the fourth embodiment. FIG. 7 is a flowchart showing a procedure of processing executed by the control device of the fifth embodiment. FIG. 8 is a flowchart showing a procedure of processing executed by the control device of the sixth embodiment. FIG. 9 is a flowchart showing a procedure of processing executed by the control device of the first modified example of the sixth embodiment. FIG. 10 is a flowchart showing a procedure of processing executed by the control device of the second modified example of the sixth embodiment. FIG. 11 is a flowchart showing a procedure of processing executed by the control device of the third modified example of the sixth embodiment. FIG. 12 is a flowchart showing a procedure of processing executed by the control device of the fourth modified example of the sixth embodiment. FIG. 13 is a flowchart showing a procedure of processing executed by the control device of the seventh embodiment. FIG. 14 is a flowchart showing a procedure of processing executed by the control device of the eighth embodiment. FIG. 15 is a flowchart showing a procedure of processing executed by the control device of the ninth embodiment.

Hereinafter, an embodiment of a fuel injection system will be described with reference to the drawings. In order to facilitate understanding of the description, the same constituent elements in each drawing are denoted by the same reference numerals as much as possible, and redundant description will be omitted.
<First Embodiment>
First, the fuel injection system 10 of the first embodiment shown in FIG. 1 will be described. The fuel injection system 10 shown in FIG. 1 is a system for injecting fuel into an internal combustion engine 20 of a vehicle. Gas fuel such as CNG is used as the fuel of the internal combustion engine 20 of the present embodiment. In FIG. 1, only one cylinder 21 of the plurality of cylinders provided in the internal combustion engine 20 is shown. The fuel injection system 10 includes a fuel tank 30, a port injection injector 40, and a direct injection injector 50.

High-pressure gas fuel is stored in the fuel tank 30. A fuel pipe 31 is connected to the fuel tank 30. The fuel pipe 31 is branched into a first branch pipe 310 and a second branch pipe 311 from an intermediate portion. A first delivery pipe 312 is connected to the tip of the first branch pipe 310. A second delivery pipe 313 is connected to the tip of the second branch pipe 311. The high-pressure gas fuel stored in the fuel tank 30 is supplied to the first delivery pipe 312 and the second delivery pipe 313 through the fuel pipe 31. The first delivery pipe 312 supplies the gas fuel to the port injection injector 40 provided in each cylinder 21 of the internal combustion engine 20. The second delivery pipe 313 supplies gas fuel to the direct injection injector 50 provided in each cylinder 21 of the internal combustion engine 20.

The fuel pipe 31 is provided with a fuel cutoff valve 32 and a regulator 33. The first branch pipe 310 is provided with the regulator 34. The fuel cutoff valve 32 can switch supply and cutoff of gas fuel from the fuel tank 30 to the delivery pipes 312 and 313 by opening and closing the fuel cutoff valve 32. The regulator 33 can adjust the pressure of the gas fuel supplied from the fuel tank 30 to the second delivery pipe 313 by changing the opening degree. The regulator 34 can adjust the pressure of the gas fuel supplied from the fuel tank 30 to the first delivery pipe 312 by changing the opening thereof.

The port injection injector 40 is provided in the intake passage 22 of the internal combustion engine 20. The port injection injector 40 injects the gas fuel supplied from the first delivery pipe 312 into the intake passage 22. The gas fuel injected from the port injection injector 40 is introduced into the combustion chamber 210 in the cylinder 21 together with the air flowing in the intake passage 22.

The direct injection injector 50 is provided in the cylinder 21 of the internal combustion engine 20. The direct injection injector 50 directly injects the gas fuel supplied from the second delivery pipe 313 into the combustion chamber 210 in the cylinder 21.
A port injection injector 40 and a direct injection injector 50 are provided in each cylinder 21 of the internal combustion engine 20 in the same arrangement.

Air is introduced into the combustion chamber 210 of each cylinder 21 of the internal combustion engine 20 from the intake passage 22 through the intake valve 23. Further, the gas fuel injected from the port injection injector 40 or the direct injection injector 50 is introduced into the combustion chamber 210. In the internal combustion engine 20, combustion of the air-fuel mixture in the combustion chamber 210 causes the piston 211 in each cylinder 21 to reciprocate. As a result, the driving force of the internal combustion engine 20 can be obtained. Exhaust gas generated by burning the air-fuel mixture in the combustion chamber 210 is exhausted to the exhaust passage 25 of the internal combustion engine 20 through the exhaust valve 24.

Next, the electrical configuration of the fuel injection system 10 will be described.
As shown in FIG. 1, the fuel tank 30 is provided with a pressure sensor 60. The pressure sensor 60 detects the fuel pressure of the fuel tank 30, more specifically, the pressure of the gas fuel stored in the fuel tank 30, and outputs a signal according to the detected fuel pressure of the fuel tank 30.

A pressure sensor 61 is provided on the first delivery pipe 312. The pressure sensor 61 detects the pressure of the gas fuel inside the first delivery pipe 312, in other words, the fuel injection pressure of the port injection injector 40, and outputs a signal according to the detected pressure of the gas fuel.

A pressure sensor 62 is provided on the second delivery pipe 313. The pressure sensor 62 detects the pressure of the gas fuel inside the second delivery pipe 313, in other words, the fuel injection pressure of the direct injection injector 50, and outputs a signal according to the detected pressure of the gas fuel.
As shown in FIG. 2, the output signals of the pressure sensors 60 to 62 are fetched by the control device 70. The control device 70 is mainly composed of a microcomputer having a CPU and a memory. The control device 70 includes a non-volatile memory 71 for storing various information. The control device 70 can acquire information on the fuel pressure of the fuel tank 30, the fuel injection pressure of the port injection injector 40, and the fuel injection pressure of the direct injection injector 50 based on the output signals of the pressure sensors 60 to 62. It is possible.

The control device 70 also captures the output signals of the various in-vehicle sensors 63. The vehicle-mounted sensor 63 includes, for example, a sensor that detects the amount of depression of the accelerator pedal, a crank angle sensor that detects the rotation angle of the crankshaft of the internal combustion engine 20, and a flow rate that detects the amount of intake air that is the flow rate of air flowing through the intake passage 22. A sensor, a temperature sensor for detecting the temperature of the exhaust gas flowing through the exhaust passage 25, a temperature sensor for detecting the temperature of the cooling water of the internal combustion engine 20, and the like are included.

The control device 70 controls the fuel injection amount of each cylinder 21 by controlling the port injection injector 40 and the direct injection injector 50 of each cylinder 21 based on various information detected by the sensors 60 to 63. The injection control is executed.
By the way, when a gas fuel is used as the fuel of the internal combustion engine 20, the injectors 40 and 50 cannot be boundary lubricated by the fuel, so compared with the case where the liquid fuel is used as the fuel of the internal combustion engine 20. The sliding parts of the injectors 40, 50 are easily worn. When the sliding parts of the injectors 40 and 50 are worn, the fuel injection amount of the injectors 40 and 50 varies, which may prevent proper fuel injection control.

On the other hand, the amount of wear of each injector 40, 50 is basically correlated with the number of times of operation of each injector 40, 50. Therefore, in the fuel injection system 10 of the present embodiment, the wear amount of each injector 40, 50 is estimated based on the number of times of operation of each injector 40, 50. In the fuel injection system 10 of the present embodiment, the durability of the entire system is improved by preferentially driving the injector having a small number of operations among the port injection injector 40 and the direct injection injector 50. There is.

Specifically, as shown in FIG. 2, the control device 70 includes a wear amount estimation unit 72 and a determination unit 73.
The wear amount estimation unit 72 counts the cumulative number of times of operation of each injector 40, 50 as an estimated value of the wear amount of each injector 40, 50. The cumulative number of operations is the total number of operations of each injector 40, 50 from the start of driving. Specifically, the non-volatile memory 71 stores the cumulative operation number NP of the port injection injector 40 and the cumulative operation number ND of the direct injection injector 50. The respective values of the cumulative number of operations NP and ND are set to zero at the start of driving the injectors 40 and 50. The wear amount estimation unit 72 increments the value of the cumulative operation number NP each time the port injection injector 40 is driven. In addition, the wear amount estimating unit 72 increments the value of the cumulative operation number ND each time the direct injection injector 50 is driven. By storing the cumulative number of operations NP, ND in the non-volatile memory 71, the information of the cumulative number of operations NP, ND is retained even when the power supply of the control device 70 is cut off from the battery after the vehicle is stopped. It is possible to do.

The determination unit 73 preferentially operates which of the port injection injector 40 and the direct injection injector 50, based on the cumulative number of operations NP, ND of the injectors 40, 50 stored in the nonvolatile memory 71. To judge.
Next, with reference to FIG. 3, a procedure of processing executed by the determination unit 73 will be specifically described.

As shown in FIG. 3, the determination unit 73 first reads the maximum operation numbers NPmax and NDmax of the injectors 40 and 50 from the nonvolatile memory 71 as the process of step S10. The maximum number of operations NPmax, NDmax is the maximum value of the number of operations of each injector 40, 50 in which an unacceptable performance change does not occur. The maximum number of operations NPmax and NDmax are set through experiments and the like, and are stored in the non-volatile memory 71 in advance. When the port injection injector 40 and the direct injection injector 50 have different structures, the maximum number of operations NPmax and NDmax may be set to different values. In the present embodiment, the maximum number of operations NPmax and NDmax correspond to the predetermined number of times.

The determination unit 73 reads the cumulative operation numbers NP and ND of the injectors 40 and 50 from the nonvolatile memory 71 as the process of step S11 following step S10. Subsequently, the determination unit 73 calculates the operable number of times NPc, NDc of each injector 40, 50 based on the following equations f1, f2 as the processing of step S12.

NPc=NPmax-NP (f1)
NDc=NDmax-ND (f2)
As the process of step S13 subsequent to step S12, the determination unit 73 determines which of the port injection injector 40 and the direct injection injector 50 is to be preferentially operated based on the operable number of times NPc, NDc of each injector 40, 50. decide. Specifically, when the operable frequency NPc of the port injection injector 40 is larger than the operable frequency NDc of the direct injection injector 50, the determination unit 73 preferentially operates the port injection injector 40. Further, when the operable number NDc of the direct injection injectors 50 is larger than the operable number NPc of the port injection injectors 40, the determination unit 73 preferentially operates the direct injection injectors 50. When the operable number of times NPc of the port injection injector 40 and the operable number of times NDc of the direct injection injector 50 have the same value, the determination unit 73 determines whether one of the port injection injector 40 and the direct injection injector 50. Operate.

After executing the process of step S13, the determination unit 73 ends the series of processes shown in FIG.
The determining unit 73 individually executes the process shown in FIG. 3 for each of the plurality of cylinders 21 of the internal combustion engine 20.

According to the fuel injection system 10 of the present embodiment described above, the actions and effects shown in the following (1) and (2) can be obtained.
(1) Since more appropriate injectors corresponding to the wear amounts of the port injection injector 40 and the direct injection injector 50 can be preferentially operated, the durability of the injectors 40, 50 for injecting gas fuel is improved. Can be made.

(2) The wear amount estimation unit 72 estimates the wear amount of each injector 40, 50 based on the cumulative number of operations NP, ND of each injector 40, 50. The determination unit 73 calculates a subtraction value obtained by subtracting the cumulative operation times NP, ND from the maximum operation times NPmax, NDmax for each of the injectors 40, 50 as shown in the above equations f1, f2, and the subtraction value is the highest. Operate the large injector preferentially. With such a configuration, it becomes easy to preferentially operate the injector having a sufficient durability.

<Second Embodiment>
Next, a second embodiment of the fuel injection system 10 will be described. Hereinafter, differences from the fuel injection system 10 of the first embodiment will be mainly described.
As shown in FIG. 4, the determination unit 73 of the present embodiment, as the process of step S14 subsequent to the process of step S11, based on the following equations f3 and f4, the cumulative operation ratios NPr and NDr of the injectors 40 and 50. To calculate.

NPr=NP/NPmax (f3)
NDr=ND/NDmax (f4)
The determination unit 73 determines which of the port injection injector 40 and the direct injection injector 50 is to be preferentially operated based on the cumulative operation ratios NPr, NDr of the injectors 40, 50 as the process of step S13 subsequent to step S14. decide. Specifically, when the cumulative operation ratio NPr of the port injection injector 40 is smaller than the cumulative operation ratio NDr of the direct injection injector 50, the determination unit 73 preferentially operates the port injection injector 40. When the cumulative operation ratio NDr of the direct injection injectors 50 is smaller than the cumulative operation ratio NPr of the port injection injectors 40, the determination unit 73 preferentially operates the direct injection injectors 50. When the cumulative operation ratio NPr of the port injection injector 40 and the cumulative operation ratio NDr of the direct injection injector 50 have the same value, the determination unit 73 determines which one of the port injection injector 40 and the direct injection injector 50. Operate.

According to the fuel injection system 10 of the present embodiment described above, the action and effect shown in the following (3) can be obtained instead of the action and effect shown in the above (2).
(3) The determination unit 73 calculates, for each of the injectors 40 and 50, a division value obtained by dividing the cumulative number of operations NP and ND by the maximum number of operations NPmax and NDmax, as shown in the above equations f3 and f4. The injector with the smallest value is activated first. With such a configuration, it becomes easy to preferentially operate the injector having a sufficient durability.

<Third Embodiment>
Next, a third embodiment of the fuel injection system 10 will be described. Hereinafter, differences from the fuel injection system 10 of the first embodiment will be mainly described.
The determination unit 73 of the first embodiment individually executes the determination process of the priority operation injector shown in FIG. 3 for each of the plurality of cylinders 21 of the internal combustion engine 20. On the other hand, the determination unit 73 of the present embodiment executes the determination process shown in FIG. 3 only on a specific cylinder of the plurality of cylinders 21 and determines the determination result different from that of the specific cylinder. By using it in other cylinders as well, the injector to be preferentially operated in other cylinders is determined.

Specifically, as shown in FIG. 5, as the processing of step S15, the determination unit 73 first gives priority to only a specific cylinder of the plurality of cylinders 21 of the internal combustion engine 20 shown in FIG. The determination process of the operating injector is executed. This determines which of the port injection injector 40 and the direct injection injector 50 is to be preferentially operated in the specific cylinder.

Next, as a process of step S16, the determination unit 73 reflects the injector determination result determined in the process of step S15 on another cylinder other than the specific cylinder. As a result, the injector provided at the same position as the injector determined to be preferentially operated in the specific cylinder is preferentially operated with respect to the other cylinders.

According to the fuel injection system 10 of the present embodiment described above, it is possible to further obtain the action and effect shown in (4) below.
(4) Since the process of determining the injector to be preferentially operated is performed only for a specific cylinder of the plurality of cylinders 21, the determination process can be simplified. Further, since the same injector is preferentially operated in each of the plurality of cylinders 21, it is possible to suppress variations in the lives of the injectors 40 and 50 among the plurality of cylinders 21.

<Fourth Embodiment>
Next, a fourth embodiment of the fuel injection system 10 will be described. Hereinafter, differences from the fuel injection system 10 of the first embodiment will be mainly described.
In the internal combustion engine 20 having the structure as shown in FIG. 1, since the direct injection injector 50 can inject the gas fuel more than the gas injection from the port injection injector 40, the charging efficiency can be improved. The output and fuel consumption of the internal combustion engine 20 can be improved. Therefore, in a situation where the load on the internal combustion engine 20 is high, it is desirable that the direct injection injector 50 be operated with priority over the port injection injector 40. Therefore, when the load of the internal combustion engine 20 is equal to or greater than the predetermined value, the determination unit 73 of the present embodiment preferentially operates the direct injection injector 50 regardless of the operable counts NPc and NDc. ing.

Specifically, as shown in FIG. 6, the determination unit 73 first determines whether or not the load Le of the internal combustion engine 20 is equal to or greater than a predetermined value Lth as the process of step S20. The load Le of the internal combustion engine 20 is a numerical representation of the load state of the internal combustion engine 20. The load state of the internal combustion engine 20 has a correlation with, for example, the rotational speed of the internal combustion engine 20 and the intake air amount. The determination unit 73 calculates the load Le of the internal combustion engine 20 from the rotational speed of the internal combustion engine 20 and the intake air amount detected by the in-vehicle sensor 63 using a map or the like. The load Le of the internal combustion engine 20 is set such that the value becomes larger as the internal combustion engine 20 goes to a high load state, and becomes smaller as the internal combustion engine 20 goes to a low load state.

When the determination unit 73 makes a negative determination in the process of step S20, that is, when the load Le of the internal combustion engine 20 is less than the predetermined value Lth, as the process of step S22, the priority operation injector shown in FIG. Execute the judgment process. Subsequently, the determination unit 73 injects the gas fuel from the priority operation injector determined in the process of step S22 as the process of step S23.

When the determination section 73 makes an affirmative determination in the process of step S20, that is, when the load Le of the internal combustion engine 20 is equal to or greater than the predetermined value Lth, as the process of step S21, the direct injection injector 50 injects the gas fuel. To do.
According to the fuel injection system 10 of the present embodiment described above, the action and effect shown in the following (5) can be further obtained.

(5) Even in a situation where the port injection injector 40 should be preferentially operated based on the operable times NPc and NDc, when the load Le of the internal combustion engine 20 is equal to or greater than the predetermined value Lth, the operable times NPc , NDc, the direct injection injector 50 injects the gaseous fuel regardless of the magnitude of the NDc. According to such a configuration, in a situation where the load of the internal combustion engine 20 is high, it is possible to improve the filling efficiency by injecting the gas fuel from the direct injection injector 50, and thus improve the fuel efficiency and output of the internal combustion engine 20. be able to.

<Fifth Embodiment>
Next, a fifth embodiment of the fuel injection system 10 will be described. Hereinafter, differences from the fuel injection system 10 of the first embodiment will be mainly described.
In the direct injection injector 50, the gas fuel cannot be injected unless the injection pressure thereof is higher than the pressure of the combustion chamber 210. Even if the injection pressure is higher than the pressure of the combustion chamber 210, if the pressure difference between the injection pressure and the pressure of the combustion chamber 210 becomes small due to the decrease of the injection pressure, the injection amount of the direct injection injector 50 will be reduced. There is a possibility that sufficient gas fuel cannot be injected due to the decrease. Therefore, when the fuel pressure in the fuel tank 30 decreases due to a decrease in the amount of gas fuel in the fuel tank 30, the injection amount of the direct injection injector 50 is likely to be insufficient, and as a result, the internal combustion engine 20 The performance may deteriorate, and it becomes difficult to use up the gas fuel in the fuel tank 30.

On the other hand, even if the fuel pressure in the fuel tank 30 is lowered to such an extent that it becomes difficult to inject fuel from the direct injection injector 50 into the combustion chamber 210, the port injection injector 40 should inject sufficient fuel. Is possible. Therefore, when the fuel pressure in the fuel tank 30 becomes equal to or lower than a predetermined value, the determination unit 73 of the present embodiment preferentially actuates the port injection injector 40 regardless of the operable counts NPc and NDc. I am trying.

Specifically, as shown in FIG. 7, the determination unit 73 first determines whether or not the fuel pressure Pf of the fuel tank 30 detected by the pressure sensor 60 is equal to or lower than the predetermined value Pth as the process of step S24. To judge. When the determination unit 73 makes a negative determination in the process of step S24, that is, when the fuel pressure Pf of the fuel tank 30 exceeds the predetermined value Pth, the priority operation shown in FIG. 3 is performed as the process of step S22. Execute the injector determination process. Subsequently, the determination unit 73 injects the gas fuel from the priority operation injector determined in the process of step S22 as the process of step S23.

When the determination section 73 makes an affirmative determination in the process of step S24, that is, when the fuel pressure Pf of the fuel tank 30 is equal to or lower than the predetermined value Pth, as the process of step S31, the gas fuel is supplied from the port injection injector 40. To jet.
According to the fuel injection system 10 of the present embodiment described above, it is possible to further obtain the action and effect shown in (6) below.

(6) Even when the direct injection injector 50 is to be preferentially operated based on the operable number of times NPc and NDc, when the fuel pressure Pf of the fuel tank 30 is equal to or less than the predetermined value Pth, the operable number of times Gas fuel is injected from the port injection injector 40 regardless of the magnitude of NPc and NDc. With such a configuration, when the fuel pressure Pf in the fuel tank 30 is low, the gas fuel is injected from the port injection injector 40, so that the gas fuel in the fuel tank 30 can be used up more reliably. Become. As a result, it is possible to extend the cruising range of the vehicle. Note that, when the gas fuel is injected from the port injection injector 40, the charging efficiency is lower than that when the direct injection injector 50 injects the gas fuel, and thus there is a concern that the output of the internal combustion engine 20 may decrease. In order to eliminate this, it is effective to supplement the output of the internal combustion engine 20, for example, by increasing the gear ratio of the transmission of the vehicle and shifting the operating point of the internal combustion engine 20 to the high rotation side.

<Sixth Embodiment>
Next, a sixth embodiment of the fuel injection system 10 will be described. Hereinafter, differences from the fuel injection system 10 of the first embodiment will be mainly described.
When the priority operation injector determination process shown in FIG. 3 is constantly performed, the injector that injects fuel may switch for each combustion cycle of the internal combustion engine 20, and the fuel injection amount may vary for each combustion cycle. There is. Therefore, it is not desirable to perform the determination process of the preferential operation injector frequently, and it is desirable to perform the determination process of the priority operation injector at a certain time interval. Therefore, in the fuel injection system 10 of the present embodiment, the priority operation injector determination process shown in FIG. 3 is performed at predetermined time intervals.

Specifically, the determination unit 73 of this embodiment executes the processing shown in FIG. 8 at a predetermined calculation cycle. As shown in FIG. 8, the determining unit 73 first determines whether or not a predetermined time has elapsed from the previous determination time of the priority actuating injector as the process of step S40.
If the determination unit 73 makes a positive determination in the process of step S40, that is, if a predetermined time has elapsed from the previous determination time of the priority actuating injector, the determination unit 73 performs the process shown in FIG. The determination process of the operating injector is executed. In addition, the determination unit 73 counts the elapsed time from the determination time point after determining the priority operation injector in the process of step S41.

When the determination unit 73 makes a negative determination in the process of step S40, that is, when the predetermined time from the previous determination time of the priority actuating injector has not elapsed, the determination unit 73 does not execute the process of step S41. That is, the determination unit 73 does not determine the priority actuating injector.
According to the fuel injection system 10 of the present embodiment described above, it is possible to further obtain the action and effect shown in the following (7).

(7) Since the priority operation injector is determined every predetermined time, it is possible to avoid frequent injector switching. As a result, it is possible to suppress variations in the fuel injection amount for each fuel cycle, and thus it is possible to suppress adverse effects on drivability and the like.

(First modification)
Next, a first modified example of the fuel injection system 10 of the sixth embodiment will be described.
As shown in FIG. 9, in the fuel injection system 10 of the present modification, a process of determining whether or not the internal combustion engine 20 has started is performed as the process of step S40. Even with such a configuration, the priority operation injector is determined every predetermined time, and therefore the same or similar action and effect as the action and effect shown in the above (7) can be obtained. ..

(Second modified example)
Next, a second modification of the fuel injection system 10 of the sixth embodiment will be described.
As shown in FIG. 10, in the fuel injection system 10 of the present modification, a process of determining whether the internal combustion engine 20 has stopped is performed as the process of step S40. Even with such a configuration, the priority operation injector is determined every predetermined time, and therefore the same or similar action and effect as the action and effect shown in the above (7) can be obtained. ..

(Third modification)
Next, a third modification of the fuel injection system 10 according to the sixth embodiment will be described.
As shown in FIG. 11, in the fuel injection system 10 of the present modification, a process of determining whether or not the vehicle has stopped is performed as the process of step S40. Even with such a configuration, the priority operation injector is determined every predetermined time, and therefore the same or similar action and effect as the action and effect shown in the above (7) can be obtained. ..

(Fourth modification)
Next, a fourth modification of the fuel injection system 10 according to the sixth embodiment will be described.
As shown in FIG. 12, in the fuel injection system 10 of the present modified example, a process of determining whether or not the fuel cut control of the internal combustion engine 20 is being performed is performed as the process of step S40. Even with such a configuration, the priority operation injector is determined every predetermined time, and therefore the same or similar action and effect as the action and effect shown in the above (7) can be obtained. ..

<Seventh Embodiment>
Next, a seventh embodiment of the fuel injection system 10 will be described. Hereinafter, differences from the fuel injection system 10 of the first embodiment will be mainly described.
In order to suppress the characteristic change of the port injection injector 40, it is desirable to replace the port injection injector 40 when the cumulative operation number NP of the port injection injector 40 is smaller than the maximum operation number NPmax. Therefore, in the fuel injection system 10 of the present embodiment, a warning number having a value smaller than the maximum operation number NPmax is provided, and when the cumulative operation number NP of the port injection injector 40 reaches the warning number, the port A warning is issued to prompt replacement of the injection injector 40. The same applies to the direct injection injector 50.

Specifically, as shown by the broken line in FIG. 2, the control device 70 further includes a warning device 80 capable of issuing a warning for prompting replacement of the injectors 40, 50. As the warning device 80, for example, a warning light provided on an instrument panel of a vehicle can be used.

The control device 70 further includes a warning unit 74 that executes a process of issuing a warning from the warning device 80 that prompts replacement of the injectors 40, 50. Specifically, the warning unit 74 executes the process shown in FIG.
As shown in FIG. 13, the warning unit 74 first reads the warning counts NPth and NDth of the injectors 40 and 50 from the nonvolatile memory 71 as the process of step S50. The warning frequency NPth of the port injection injector 40 is set to a value smaller than the maximum operation frequency NPmax of the port injection injector 40. Further, the warning frequency NDth of the direct injection injector 50 is set to a value smaller than the maximum operation frequency NDmax of the direct injection injector 50. In the present embodiment, the number of warnings NPth and NDth corresponds to a predetermined number of times.

The warning unit 74 reads the cumulative operating numbers NP and ND of the injectors 40 and 50 from the nonvolatile memory 71 as the process of step S51 following step S50. Subsequently, the warning unit 74 determines whether or not the cumulative number of operations NP, ND is equal to or more than the number of warnings NPth, NDth as the process of step S52. If the cumulative operation number NP of the port injection injectors 40 is the warning number NPth or more, or if the cumulative operation number ND of the direct injection injectors 50 is the warning number NDth or more, the warning unit 74 affirms in the process of step S52. to decide.

If the determination in step S52 is affirmative, the warning unit 74 issues a warning from the warning device 80 as the process in step S53. Specifically, when the cumulative number of operations NP of the port injection injector 40 is equal to or greater than the number of warnings NPth, the warning unit 74 issues a warning from the warning device 80 to prompt replacement of the port injection injector 40. Further, the warning unit 74 issues a warning from the warning device 80 to prompt replacement of the direct injection injector 50 when the cumulative number of operations ND of the direct injection injector 50 is equal to or more than the number of warnings NDth.

According to the fuel injection system 10 of the present embodiment described above, the action and effect shown in the following (8) can be further obtained.
(8) Since it is possible to prompt replacement of each injector 40, 50 before the cumulative number of operations NP, ND of each injector 40, 50 reaches the maximum number of operations NPmax, NDmax, use of an injector that may deteriorate performance Can be avoided. Therefore, it becomes possible to secure reliability.

<Eighth Embodiment>
Next, an eighth embodiment of the fuel injection system 10 will be described. Hereinafter, differences from the fuel injection system 10 of the seventh embodiment will be mainly described.
The determination unit 73 of this embodiment executes the process shown in FIG. As shown in FIG. 14, the determination unit 73 first reads the maximum operation times NPmax and NDmax of the injectors 40 and 50 from the nonvolatile memory 71 as the process of step S60. Subsequently, the determination unit 73 reads the cumulative operation numbers NP and ND of the injectors 40 and 50 from the nonvolatile memory 71 as the process of step S61.

The determination unit 73 determines whether or not the cumulative number of operations NP, ND of the injectors 40, 50 has reached the maximum number of operations NPmax, NDmax as the process of step S62 subsequent to step S61. When the determination unit 73 makes an affirmative determination in the process of step S62, the determination unit 73 determines whether or not there is an injector whose cumulative number of operations has not reached the maximum number of operations as the process of step S63.

When the determination section 73 makes an affirmative decision in the process of step S63, as the process of step S64, the injector whose cumulative operation number has not reached the maximum operation number is preferentially operated, and as the process of step S65, the accumulation is performed. The injectors that have reached the maximum number of operations are prohibited from operating. For example, when the cumulative number of operations NP of the port injection injector 40 is greater than or equal to the maximum number of operations NPmax and the cumulative number of operations ND of the direct injection injector 50 is less than the maximum number of operations NDmax, the determination unit 73 determines that the direct injection injector is While 50 is preferentially operated, the operation of the port injection injector 40 is prohibited.

On the other hand, if the determination unit 73 makes a negative determination in the process of step S63, the determination unit 73 executes the determination process of the priority operation injector shown in FIG. 3 as the process of step S66 to determine the injector to be operated preferentially. To do.
According to the fuel injection system 10 of the present embodiment described above, the operation and effect shown in the following (9) can be obtained.

(9) Since it is difficult to use the injector whose cumulative number of operations has reached the maximum number of operations, it is possible to further improve reliability.
<Ninth Embodiment>
Next, a ninth embodiment of the fuel injection system 10 will be described. Hereinafter, differences from the fuel injection system 10 of the first embodiment will be mainly described.

As shown by the broken line in FIG. 2, each injector 40, 50 of this embodiment is provided with identification information storage units 41, 51. Identification information IDp and IDd are stored in the identification information storage units 41 and 51, respectively. The identification information IDp is information that can identify each individual of the port injection injector 40. The identification information Dd is information that can identify each individual direct injection injector 50. For example, IC chips can be used as the identification information storage units 41 and 51. The identification information IDp and IDd are also stored in the non-volatile memory 71 when the control device 70 obtains them from the injectors 40 and 50.

The determination unit 73 of this embodiment executes the processing shown in FIG. The process shown in FIG. 15 is executed for each of the port injection injector 40 and the direct injection injector 50, but in the following, for convenience, the process shown in FIG. 15 is executed for the port injection injector 40. The case will be described as an example.

As shown in FIG. 15, the determination unit 73 first acquires the identification information IDp from the port injection injector 40 as the process of step S70. Further, the determination unit 73 reads the identification information IDp of the port injection injector 40 stored in the nonvolatile memory 71 as the process of step S71.

The determination unit 73 determines whether or not the identification information IDp acquired from the port injection injector 40 and the identification information IDp read from the nonvolatile memory 71 match as the processing of step S72. The determination unit 73 determines that the port injection injector 40 has been replaced when the identification information is different. In this case, as the processing of the determination unit 73 and step S73, the cumulative number of operations NP of the port injection injector 40 is set to zero to reset the cumulative number of operations NP. Further, the determination unit 73 causes the nonvolatile memory 71 to store the identification information IDp acquired this time from the port injection injector 40 as the process of step S74. Thereby, the identification information IDp of the new port injection injector 40 after replacement is stored in the non-volatile memory 71.

According to the fuel injection system 10 of the present embodiment described above, the action and effect shown in the following (10) can be further obtained.
(10) When the injectors 40, 50 are replaced, the cumulative number of operations NP, ND is automatically reset, so that the cumulative number of operations NP, ND can be appropriately counted.

<Other Embodiments>
In addition, each embodiment can also be implemented in the following forms.
-The internal combustion engine 20 of each embodiment has two injectors, the port injection injector 40 and the direct injection injector 50, but the number of injectors provided in the internal combustion engine 20 is not limited to two, but three or more. May be Further, the internal combustion engine 20 may include a plurality of either one of the port injection injector and the direct injection injector.

In the fuel injection system 10 of each embodiment, the amount of change in the lift amount of each injector 40, 50, the amount of change in the injection amount, and the change in responsiveness instead of the cumulative number of operations NP, ND of each injector 40, 50. You may use quantity etc.
The internal combustion engine 20 to which the fuel injection system 10 of each embodiment is applied is not limited to the structure in which the injectors 40 and 50 are mounted in each cylinder 21, but may be located upstream of the branch portion of each cylinder 21 in the intake passage 22. It may have a structure in which a common port injection injector is provided in a part.

The fuel injection system 10 of each embodiment is applicable not only to the internal combustion engine 20 of the vehicle but also to any engine such as a fuel cell.
One or more of the control device 70 and the control method thereof described in the present disclosure are provided by configuring a processor and a memory programmed to execute one or more functions embodied by a computer program. It may be realized by a plurality of dedicated computers. The control device 70 and the control method thereof described in the present disclosure may be realized by a dedicated computer provided by configuring a processor including one or more dedicated hardware logic circuits. The control device 70 and the control method thereof described in the present disclosure are configured by a combination of a processor and a memory programmed to execute one or more functions, and a processor including one or more hardware logic circuits. It may also be realized by one or more dedicated computers. The computer program may be stored in a computer-readable non-transitional tangible recording medium as an instruction executed by a computer. The dedicated hardware logic circuit and the hardware logic circuit may be realized by a digital circuit including a plurality of logic circuits or an analog circuit.

-The present disclosure is not limited to the above specific examples. A person skilled in the art appropriately modified the above-described specific examples is also included in the scope of the present disclosure as long as the features of the present disclosure are provided. Each element included in each of the above-described specific examples, and the arrangement, conditions, shape, and the like thereof are not limited to those illustrated, and can be appropriately changed. The respective elements included in the above-described specific examples can be appropriately combined as long as there is no technical contradiction.

Claims (19)

1. At least two injectors (40, 50) for injecting gas fuel into the engine (20), a fuel tank (30) for storing gas fuel, and gas fuel from the fuel tank to the injectors, respectively. A fuel injection system having a delivery pipe (312, 313) for supplying,
   A wear amount estimating unit (72) for estimating the wear amount of each of the plurality of injectors,
   A fuel injection system, comprising: a determination unit (73) that determines which one of the injectors is to be preferentially operated based on the wear amount of each injector estimated by the wear amount estimation unit. ..
2. The fuel injection system according to claim 1, wherein the engine is an internal combustion engine (20).
3. The fuel injection system according to claim 2, wherein at least two plural injectors are provided in each cylinder (21) of the internal combustion engine.
4. The fuel injection system according to any one of claims 1 to 3, wherein the wear amount estimation unit estimates the wear amount of the injector based on the cumulative number of times of operation of the injector.
5. The fuel injection system according to claim 4, wherein the determination unit calculates a subtraction value obtained by subtracting the cumulative number of operations from a predetermined number of times for each of the plurality of injectors, and preferentially operates the injector with the largest subtraction value. ..
6. The fuel injection system according to claim 4, wherein the determination unit calculates a divided value obtained by dividing the cumulative number of times of operation by a predetermined number of times for each of the plurality of injectors, and preferentially operates the injector having the smallest divided value. ..
7. In each cylinder of the engine, a plurality of the injectors are provided in a similar arrangement,
   The determination unit,
   With respect to the plurality of injectors provided in a specific cylinder among the plurality of cylinders, while performing a process of determining an injector to be preferentially operated,
   7. An injector provided at the same position as an injector determined to be preferentially operated in the specific cylinder is preferentially operated with respect to another cylinder different from the specific cylinder. The fuel injection system according to claim 1.
8. The fuel injection system according to any one of claims 1 to 7, wherein at least one of the plurality of injectors is a direct injection injector (50) that directly injects gas fuel into a cylinder of the engine.
9. The fuel injection system according to claim 8, wherein the determination unit operates the direct injection injector regardless of the wear amount when the load of the engine is a predetermined value or more.
10. The fuel injection system according to any one of claims 1 to 6, wherein at least one of the plurality of injectors is a port injection injector (40) that injects gas fuel into an intake passage of the engine.
11. Further comprising a pressure sensor (60) for detecting a fuel pressure inside the fuel tank,
    The fuel injection system according to claim 10, wherein the determination unit operates the port injection injector regardless of the amount of wear when the pressure inside the fuel tank is equal to or lower than a predetermined value.
12. The fuel injection system according to any one of claims 1 to 11, wherein the determination unit executes a process of determining an injector to be preferentially operated at predetermined time intervals.
13. The fuel injection system according to any one of claims 1 to 11, wherein the determination unit executes a process of determining an injector to be preferentially operated when the engine is started or after the engine is stopped.
14. The fuel injection system according to any one of claims 1 to 11, wherein the determination unit executes a process of determining an injector to be preferentially operated when the vehicle is stopped.
15. The fuel injection system according to any one of claims 1 to 11, wherein the determination unit executes a process of determining an injector to be preferentially operated during fuel cut control of the engine.
16. The warning unit (74) for issuing a warning based on a cumulative number of times of operation of any one of the plurality of injectors is a predetermined number or more, further comprising: a warning unit (74). Fuel injection system.
17. The determination unit is configured such that at least one of the plurality of injectors provided in a specific cylinder of the plurality of cylinders of the engine has a cumulative number of operations of a predetermined number of times, and a plurality of injectors provided in the specific cylinder. In the case where there is an injector whose cumulative number of operations has not reached the predetermined number of times among the injectors, the injector whose cumulative number of operations has not reached the predetermined number of times is preferentially operated, and the cumulative number of operations is The fuel injection system according to any one of claims 1 to 16, wherein the operation of the injector that has reached a predetermined number of times is prohibited.
18. The fuel injection system according to any one of claims 1 to 17, wherein the determination unit determines whether or not the injector provided in the engine has been replaced, based on identification information provided in the injector.
19. The fuel injection system according to claim 18, wherein, when it is determined that the injector provided in the engine has been replaced, the determination unit resets the cumulative number of times of operation of the corresponding injector.

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